Warsaw pact would most likely not use nuclear weapons against the mainland targets of any nuclear armed nations. No matter what the drills say and predict they would do, they arent idiots.
So, the nuclear exchange would be limited to destroying C and E europe, both of which serves the interestes of W europe and Russia. So. From the French PoV it would work, Warsaw pact gathers enough supplies near units and doesnt bother about long supply lines that can be cut, hits with a surprise attack and advances along the cover of low yield theather weapons at all NATO supply and troop targets in non-nuclear armed nations, making absolutely sure they are low yield so that they just mess with the nato ability to respond and not entirely eliminate it. Force nato to keep the response low yield and over the theather by not striking any French or UK land installations and not crossing UK or French airspace.
Stop at the French border and at the Italian Borders, Dont invade Swiss and thats about as far as the USSR can go. Mainland France is immediate nuclear exchange and Mainland Italy too most likely.
So, it works. Kept the Cold War from going hot since all USSR military predictions would end in nuclear holocaust if military solution is sought. Its only pure luck that this understanding didnt translate into a massive USSR military reduction in the 70's and 80's and a focus on ideological brainwashing of the population. Had that happened we would all speak russian.